Find Your Portrait
After you log in to StarCraft II, your current icon is displayed in the upper right corner of the screen along with your name and current achievement points. If you mouse over your portrait, your character code will be displayed.
View All Portraits
To view all the portraits you can earn in the game, click your portrait in the upper right corner, then click the "Rewards" button to the left of the window that appears below. On the drop-down menu to the right above the portraits, make sure "All" is selected. This is a display of all the portraits currently in use in StarCraft II. If you can't use a portrait it will be grayed out with a lock icon displayed over it, but you can mouse over it to get a full color view anyway.
Set New Portrait
Any of the portraits you can set will be lit up with a blue border, and with a date displayed below; this is the date you earned the portrait. To set any of these portraits, simply click the one you want and it will change instantly. If you want to browse only the available portraits, select "Earned" from the drop-down menu.
Earn Portraits
Mouse over any of the gray portraits to find out what you need to do to earn each one. For example, you may need to win a certain number of multiplayer games or complete all the achievements from a certain mission arc in the campaign. Once you know what to do for a specific portrait you can go back to finish whatever you need to do. Some of these are very challenging, and some require a lot of patience, but the reward is unlocking some rare portraits that you can show off to anyone who sees your profile.